The invention relates to a dryer with reduced noise development, a fan and an impeller suitable therefor and also to a method for producing the impeller. The invention relates in particular to a fan with a specially shaped impeller as well as to a dryer containing this fan and to the impeller contained in this dryer or fan.
In dryers, especially tumble dryers, laundry contained in a drum that is normally rotating is dried by having a heated stream of air directed through the drum and thereby through the laundry, with said stream of air being capable of extracting moisture from the wet laundry, gradually drying the laundry in the process.
The stream of air supplied (“process air flow”) is heated up in a feed line before the drum (“laundry drum”) by means of a heating device and after passing through the laundry in the drum is either directed to the outside (vented-air tumble dryer) or fed to a heat exchanger in which the air is cooled and the moisture is precipitated from it as condensate. A fan which features an impeller (also called a “drum impeller” or “radial fan wheel”) is generally used to propel the air. The noise generated during operation of a dryer is a disadvantage and the fan propelling the process air in particular contributes to said noise.
EP 0 702 105 B1 describes a housing for a fan in a domestic appliance, especially in a domestic tumble dryer which makes it possible to reduce the noise arising and to damp down noise which has arisen. The housing features a radial fan wheel which is installed so that it can rotate within a spiral casing and to which the air is fed axially, with the spiral casing being separably surrounded by a casing wall with wall shape which is matched to the spiral contour and extends at a distance from it, of a shell, and means are provided for maintaining the distance.